Clutch and brake for selector for automatic telecommunication equipment



. v g- 22, 1950 G D. c aLssoN :rm. 2,519,695

CLUTCH AND BRAKE FOR SELECTORS FOR AUTOMATIC TELECOMMUNICATION EQUIPMENTFiled Aug. 11, 1947 2 Sheets-Sheet 1' mum II I I mm M n ii'l um A 8 22,1950 G D. OLSSON ETALY 2,519,695

CLUTCH AND BRAKE FOR SELECTORS FOR AUTOMATIC TELECOMMUNICATION EQUIPMENTFiled Aug. 11, 1947 2 Sheets-Sheet 2' III, I

Patented Aug. 22, 1950 UNITED STATES PATENT OFFICE CLUTCH AND BRAKE FORSELECT R FOR AUTOMATIC TELE'COMMUNECA- TI'ON EQUIPMENT Gunnar Daniel015505 and Nils Fabian Bjorkman.

. Stockholm, Sweden Application August 11, 1947, Serial No. 767,942 InSweden January 11, 1943 Section 1, Public Law 694 August 8, 1946 Patentexpires January 11, 1963 telecommunication, the function of V which ishighly independent of deformations of the impulses used, for instance onaccount of long lines causing a delay due to the great capacity or baddials.

Another object-isto provide a driving clutch and brake deviceinselectorsfor telecommunication, which in spite of great simplicity inconstruction renders a very quick and, nevertheless, safe selection,numerical as well as unnu merical, possiblev Other objects, advantagesand meritorious features of our invention will more fully appear fromthe following description, appended claims and accompanying drawings,wherein:

Figures 1 and2 are a side view and atop 'view, respectively, of ourimproved selector.

- Fig. 3 is a cross-sectional view taken on'the line I II-III of Fig. 1.

i Fig. 4 il-lustratesa structural element.

Fig/5 illustrates diagrammatically the shape of three cooperating wheelsof the selector.

- In the drawing I designates a bottom plate to which two angularsupports 2 and 3 are attached, which supports are formed as bearings fora shaft; 4. said shaft is through a gear 5 connected with a drive shaftthat, preferably, is

common to several selectors. The shaft 4 is fixed in longitudinaldirection by the downwardly bent end of the support 2 which end extendsin a slot provided in a, bushing I firmly attached to the shaft 4. Inanother slot there is firmly arranged a leaf spring 8 that bears at itsouter ends against a drive wheel 9 in the form of a crown'wheel andholds said wheel pressed against a flange 31' provided on a sleeve Illwhich is firmly attached to the shaft 4 and about which the crown wheel9 is rotatably arranged. The leaf spring 8 has such a tension that thedrive wheel normally is rotated by theshaft 4. The

form of the detailswill be best seen in Fig. 3.

About the shaft 4 there is further provided a sleeve II that is movablefreely on the shaft and is at one end firmly connected with a couplingwheel l2 formed as a double crown wheel. The bushing ll extends througha central aperture 32 of a stop wheel l2 which is likewise formed as a.crown wheel. The bushing H is also provided with two flanges 15 betweenwhich a fork l6 opcrates. Said fork is attached to the armature of aclutch magnet ii and is normally held in returned position by a returnspring IS. The clutch magnet i7 is omitted in Fig. 2 so that this a.figure better illustrates details located behind the magnet. The shaft4 carries further a sleeve 59 turnable relatively to said shaft andhaving mounted thereon three contact brushes 2D. The position of saidsleeve is fixed in longitudinal direction by the downwardly bent end ofthe angular support 3 which end extends into a slot in the sleeve is andwhich may be similar in construction to the bushing l and the angularsupport 2. The sleeves H and is are connected by means of a springcoupling comprising a leaf spring 26 preferably of the form shown inFig. 4 and attached to the sleeve H at its centre. The ends of thespring 2! are attached to an arm 22 mounted on the sleeve I9. Thus, thespring 2| admits a displacement of the sleeve H in the direction of theshaft 4 though said sleeve H is non-rotatably connected with the sleevel9 which latter is unmovable in the direction of the shaft l. Thecontact brushes cooperate in a, manner known per se with a contact bank23 of a nature usually employed in such rotary switches.

The form of the teeth on the crown wheels 9, i2 and M and the adjustmentof the position of the latter relatively to each other are of greatimportance for the operation of the selector. Fragments of the crownwheels are shown diagrammatically on an enlarged scale in Fig. 5.

As will be seen of Figure 5 the drive wheel 9 and the coupling wheel l2are provided with teeth 24 and 25 respectively the profile of which havethe form of right triangles, one of the smaller sides of said trianglesconstituting the base of the tooth and the other smaller side being theedge of the surface subjected to the load. The coupling wheel is on itsother side provided with teeth 26 having a rectangular profile andcooperating with teeth Zion the fixed stop wheel M. The teeth 27comprise on one hand a sloping a, on the other hand a curved surface bthe curvature of which substantially conforms to the path of movement ofthe teeth 26 determined by the speed of rotation and the acceleration inthe direction of the shaft Li of the coupling wheel 82 when the latteris coupled with the stop wheel it. Further the distance between saidstop wheel, and the drive wheel 9 is so chosen that the coupling wheell2 may only be disconnected from the drive wheel 9 when the teeth 2%face the clearings 28 between the teeth 28 or are so close up to theseclearings that on the one hand 3 by the momentum of the coupling wheell2 and on the other hand by the force acting in the direction of theshaft on said wheel the teeth 23 are urged into complete engagement withthe clearings between "the teeth 2? by sliding of the teeth as along thecurved surfaces b of the teeth 3i. This is attained due to the fact thatthe distance l1 exceeds the distance 62 by nearly the hei ht of theteeth 26 but is smaller than the distance is by more than said height.

In the o eration of the selector the starting is accomplished. byswitching in the magnet N. Then the coupling wheel E2 is coupled withthe continuously rotating drive wheel 9 by means of the fork i5. wheel52 is not disconnected from the stop wheel in the moment when the teeth26 and 25 touch each. other, the teeth .2? being provided with slopingsa along which the test 26 may slide during that portion of thlongitudinal movement of the coupling wheel when the teeth 2!; and 25are engaged. It may, however, occur that the tops of the teeth will abutagainst the to -s oi the teeth 24. prevent the selector underunfavorable circumstances by this reason from being stopped or the teethfrom being deformed the drive wheel 9 's longitudinally displaoeable sothat to teeth rose along 1 :l-fi' the sic-pings a said wheel isdisplaced in the direction of oupling, said displacement beingcounteracted by the leaf spring 8. The latter also serves as a frictioncoupling for the drive wheel so as to admit the latter to relatively tothe shaft s when said wheel is stopped. Just before the selector arms 2treach the coupli ositi n the coupling magnet ii is demagnet ed. "iereturn spring is then tries to bring the coupling wheel back the initialposition. this is prevented by the abutment of the teeth it of thecoupling wheel i2 against the teeth it f the stop wheel it. Thus, thecoup wheel :2 will be held in engagement with the drive wheel 9 and isnot disconnected before the eeth 2:"; have moved such a distance to theleft (Figure 5) along the curved surfaces is that the coupling wheel iscertain continues to the in position where it is steppe To position inwhich the coupling wheel 52 etely gears into the stop wheel i there is icorresponding operative position of the contact As will be seen thedisconnection of net may be varied within a relaod without the desiredadjustbeing Further, a rotation. of the contact invention may be cariother types of selectors Q: cam plates or the like, selecght movingcontact brushes and As said hereinbefore the coupling not necessarily beof the so on). It is only necessary to adapt the coupling and stopdevice to the selector construction in question without departing fromthe principle of the invention. It will often be sufficient to introduce'a' suitable gearing between the coupling member and the selector arms.

Further, it is not necessary that the drive, coupling and stop membersare coaxially arranged. ihey may lso be arranged in other ways so as tosuit the construction of the selector in question.

From the foregoing, it will be understood that numerous changes inconstruction and arrangement of the parts might be resorted to withoutdeparting from the spirit of the invention as defined by the claims.

What we claim is:

1. In a selector for telecommunication equipments, a continuouslyrotatable driving member, a fixed stop-member and a movable member to bebrought into engagement alternately with said driving-member and saidstop-member, said movable member having a number of teeth cooperatingwith a number of recesses provided in said stop-member, which teeth andthe portions between said recesses are constructed and arranged to holdsaid movable member, when it is operated for moving towards saidstop-member, in engagement with said driving member if said teeth andrecesses do not face each other, but to permit disconnecting of saidmovable member from said driving member and to center said movablemember when it substantially reaches a position of engagement with saidstop-member.

2. In a selector for telecommunication equipments, a continuouslyrotatable driving crown wheel, a fixed crown wheel and a double crownwheel to be displaced between said driving crown wheel and said fixedcrown wheel, said crown wheels being coaxially arranged, said doublecrown wheel and said driving crown Wheel having clutch teeth cooperatingwith each other, whereas said double crown wheel and said fixed crownwheel are provided with stop teeth 00- operating with each .other, thedistance between said clutch teeth and said stop teeth on said doublecrown wheel exceeding the distance between the tops of the stop teeth ofsaid fixed crown wheel and the tops of the clutch teeth of said drivingcrown wheel by a less distance than the height of said clutch teeth, thefirstsaid distance on the other hand being smaller than the distancebetween the bottom of the clearings between the stop teeth of said fixedwheel and the tops of the clutch teeth of said driving crown. wheel bymore than said height.

3. In a selector for telecommunication equipments, a continuouslyrotatable driving crown wheel, a fixed crown wheel and a double crownwheel to be displaced between said driving crown wheel and said fixedcrown wheel, said crown wheels being coaxially arranged, said doublecrown wheel and said driving crown wheel having clutch teeth cooperatingwith each other, whereas said double crown wheel and said fixed crownwheel are provided with stop teeth cooperating with each other, the stopteeth of said double crown wheel having a substantially rectangularprofile, whereas the stop teeth of said fixed .crown wheel are formed,seen in the direction of rotation of said double crown wheel,

with a sloping and a curved surface, the curvature of said surfacesubstantially corresponding to the moving path of the stop teeth of saiddouble crown wheel when the latter is moving for engagement with saidfixed wheel.

4. In a selector for telecommunication equipments, a continuouslyrotatable driving crown wheel, a fixed crown'wheel and a double crownwheel to be displaced between said driving crown wheel and said fixedcrown wheel, said crown wheels being coaxially arranged, said doublecrown wheel and said driving crown wheel having clutch teeth cooperatingwith each other, whereas said double crown wheel and said fixed crownwheel are provided with stop teeth cooperating with each other, the stopteeth of said double crown wheel having a substantially rectangularprofile, whereas the stop teeth of said fixed crown wheel are formed,seen in the direction of rotation of said double crown wheel, with asloping and a curved surface, the curvature of said surfacesubstantially corresponding to the moving path of the stop teeth of saiddouble crown wheel when the latter is moving for engagement with saidfixed wheel, whereas the profile of said clutch teeth has the form of aright triangle, one of the smaller sides of said triangle being the baseof a clutch tooth and the other smaller side being the edge of thesurface subjected to the load by a cooperating tooth,

5. In a selector for telecommunication equipments, a continuouslyrotatable driving crown wheel, a fixed crown wheel, a double crown wheelto be displaced between said driving crown wheel and said fixed crownwheel, said crown wheels being coaxially arranged, said driving crownwheel being mounted on a continuously rotatable driving shaft in such amanner that it is dis- 6 placeable in longitudinal direction androtatable on said shaft, a bushing on said shaft, a flange on saidbushing, and a spring operating substantially in the direction of saidshaft and pressing said driving crown wheel against said flange, saiddouble crown wheel and said driving crown wheel having clutch teethcooperating with each other, whereas said double crown wheel and saidfixed crown wheel' are provided with stop teeth cooperating with eachother, the distance between said clutch teeth and said stop teeth onsaid double crown wheel exceeding the distance between the tops of thestop teeth of said fixed crown wheel and the tops of the clutch teeth ofsaid driving crown wheel by a less distance than the height of saidclutch teeth, the first said distance on the other hand being smallerthan the distance between the bottom of the clearings between the stopteeth of said fixed wheel and the tops of the clutch teeth of saiddriving crown wheel by more than said height.

GUN NAR DANIEROLSSON. NILS FABIAN BJORKMAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,255,143 Ebeling Feb. 15, 19181,279,893 McQuarrie Sept. 24, 1918 1,531,134 Richard Mar. 24, 19251,725,044 Aldendorff Aug. 20, 1929

